1. Field of the Invention
The present invention relates to material distributors, and, more particularly, to selective material distributors.
2. Description of the Related Art
Agricultural or farm implements that apply seed, fertilizer, or other particulate (granular) matter to a surface (“farm field”) typically have one or more central hoppers or tanks that are loaded with the particulate matter. The hoppers have or are associated with a metering device, which is typically a rotating element, that meters the particulate matter from the hoppers into a set of distribution channels, such as conduits, hoses, etc., that are flow coupled to the individual row units, or seed boxes associated with the individual row units. In many implementations, a blower system provides a turbulent air stream into which the particulate matter is entrained to pass the particulate matter through the distribution channels and ultimately to the individual row units. Such air seeders can take many forms and use various configurations to apportion the correct amount of particulate matter evenly throughout the distribution channels so that the particulate matter is deposited onto the farm field in a uniform and consistent manner.
One type of air seeder uses a large conduit to convey all the metered product to a first hollow distributor or manifold at which the particulate product is divided into a number of secondary streams evenly using evenly sized and spaced outlet ports. The secondary streams are fed to secondary headers, with each secondary header providing additional division and distribution of the secondary streams before the air/product streams are fed to the individual row units.
Another type of air seeder uses a metering roller that is segmented into a number of sections, with each section of the metering roller communicating with a dedicated set of secondary headers. With this type of air seeder, the product is mechanically metered and separated into different streams or runs and each stream is fed to a secondary header that provides additional division and distribution of the air/product streams before being fed to the individual row units.
A third type of air seeder avoids the use of secondary headers and the downstream division that such secondary headers provide. These air seeders use a metering roller that is large enough to feed product to each of the row units directly.
Regardless of the type of air seeder used, due to the increasing cost of seed and fertilizer, the agronomic disadvantage and waste associated with redundant application of seed and fertilizer, and the increasing size of seed drills, efforts have been made to selectively shut off the flow of product to the secondary headers which allows the seed drill to traverse previously seeded land without necessarily reapplying seed or fertilizer while the seed drill is used to apply particulate matter to nearby unseeded land. For air seeders having segmented or direct feed metering rollers, sectional control can be achieved by preventing the flow of product to the metering roller. When starving the roller by mechanically stopping the flow of product by using a gate or similar structure or by not rotating the roller, the roller cannot meter product downstream.
It will thus be appreciated that achieving sectional control is relatively straightforward for air seeders having segmented or direct feed metering rollers. However, for an air seeder that uses a distribution manifold and several downstream secondary headers to distribute particulate matter to the individual row units, sectional control is considerably more difficult. That is, if air flow is stopped to one of the outlet ports of the main header or manifold, the downstream channel may become plugged by the residual product thereby causing an issue when the air flow through the stopped outlet port resumes. If the channel becomes plugged, the application devices that are fed by the plugged channel will not be able to apply product to the field and will result in inconsistent and undesirable application of the seed and/or fertilizer.
One known device that can overcome some of these problems is described in U.S. Pat. No. 8,635,963 to Friggstad. The material distributor described in Friggstad utilizes selectively operable valves to block outlets of a tower-type header from receiving material from a material tank or other source, at which point pressurized air can be blown into the outlet to evacuate any material that might still be in the outlet. While the device described in Friggstad is capable of accomplishing its intended purpose, material distributors with shapes other than towers could provide additional advantages.
What is needed in the art is a material distribution system that overcomes some of the disadvantages of prior art devices.